Apparatus for reading RFID tags are generally known and serve, for example, to identify articles provided with the RFID tags.
Products can in particular be marked with RFID tags to identify and localize the products. The spatial detection of products marked with RFID tags frequently takes place by means of fixed-position reading gates. These reading gates can be arranged, for example, at entrances and exits of warehouses.
It is disadvantageous with such reading gates that the stock in a warehouse can admittedly be determined. However, the exact position of the respective products (or of the RFID tag identifying the products) inside the warehouse is unknown.
The problem additionally arises in the position determination of RFID tags that an exact localization of the RFID tag is only possible with difficulty in the reception range of the RFID reader. In addition, passive RFID tags are often used for cost reasons that can only transmit a response signal in response to a radio signal (or generally to an excitation signal) of the RFID reader. The time behavior between the radio signal and the response signal can in this respect not be described more accurately so that passive RFID tags cannot e.g. be used for time-of-flight measurements (signal transit time measurements) for a distance measurement.
It is therefore the underlying object of the invention to provide a position determination apparatus that makes it possible to detect passive RFID tags and to determine the positions of the RFID tag.